N-Fluoropyridinium salts provide a new system of fluorinatingagents by which a wide range of nucleophilic substrates differing in reactivity can be fluorinated due to the varying degree of fluorinating power and also fluorinated very selectively through structural alteration. The scope of selective fluorination should be broadened considerably on the basis of the present results. The N-fluoropyridinium
Synthesis of C-6 fluoroandrogens: Evaluation of ligands for tumor receptor imaging
作者:Yearn Seong Choe、John A. Katzenellenbogen
DOI:10.1016/0039-128x(95)00009-f
日期:1995.5
Seven androgens, substituted with fluorine at C-6, were prepared as potential imaging agents for androgen receptor-positive prostate tumors and were evaluated in vitro in terms of their lipophilicity and their relative binding affinities (RBA, relative to R 1881 = 100) for the androgen receptor and for sex steroid binding protein. Introduction of a fluorine atom into the C-6 position of an androgen generally decreases binding affinity to the androgen receptor, except in the two cases: 6 alpha-fluoro-19-nor-testosterone (RBA = 41.6 versus 30.6 for the unsubstituted steroid) and 6 alpha-fluoro-19-nor-testosterone (RBA = 8.9 versus 6.6). Receptor binding of the C-6 fluoro-androgens is also stereospecific, showing higher binding affinities for the alpha-epimers compared to the corresponding beta-epimers (4:1-15:1). Binding affinity to sex steroid binding protein is the lowest with 19-nor-testosterone, which is also the least lipophilic androgen studied. Based on the binding properties of compounds in this series, 6 alpha-fluoro-19-nor-testosterone appears to have the most promise as a turner imaging agent.
Synthesis of halogenated steroid hormones—II
作者:A. Bowers、H.J. Ringold
DOI:10.1016/s0040-4020(01)82606-5
日期:1958.1
Fission of 3β-acetoxy-5α-,6α-epoxides in the cholestane, androstane and pregnane series with boron trifluoride etherate afforded the corresponding 3β-acetoxy-5α-hydroxy-6β-fluoro compounds. By appropriate manipulation of these fluorohydrins 6α-fluorocholestenone and the biologically interesting 6α- and 6β-fluorotestosterone and 6α- 6β-fluoroprogesterone were prepared.